This invention relates to polyols containing one or more tertiary amine atoms, which are prepared in a Mannich condensation reaction to form a tertiary amine-containing intermediate which is subsequently alkoxylated.
Polyol precursor materials made by alkoxylating a Mannich condensation product (Mannich polyols) are known to be useful in preparing certain types of polyurethanes. Because these Mannich polyols contain tertiary nitrogen atoms, they are often auto-catalytic, i.e. are sufficiently reactive with isocyanate groups that they can be used to prepare polyurethanes with reduced levels of urethane catalysts, or even none at all. These Mannich polyols are typically of low equivalent weight, which makes them particularly suited to preparing rigid polyurethane foam, although their use as a crosslinker in semiflexible polyurethane foams is known as well. See U.S. Pat. No. 4,371,629.
The Mannich polyols used in polyurethane foams are prepared by alkoxylating a condensation product of phenol or a substituted phenol, formaldehyde, and diethanol amine. Such Mannich polyols are described, for example, in U.S. Pat. Nos. 3,297,597, 4,137,265 and 4,383,102, incorporated herein by reference. Although these Mannich polyols are useful in certain applications, such as in making high density spray foam, they are often too reactive to be useful in many other applications where their use might be otherwise beneficial. Another problem with many Mannich polyols is that they tend to be very viscous. This viscosity makes them very difficult to process in many types of commercial foam equipment.
Accordingly, it would be desirable to provide a Mannich polyol which is of lower reactivity than conventional Mannich polyols and which has a viscosity such that it can be processed on the equipment used in a wide range of applications.